Merck Reveals Side Effects From Niacin Study

Matthew Herper
,
Forbes Staff
I cover science and medicine, and believe this is biology's century.

Merck revealed the serious side effects that cropped up in a failed study of its niacin-containing heart drug, Tredaptive, in a letter to doctors where the treatment is approved. The letter recommends that doctors not start new patients on Tredaptive, but says patients who are on the drug can keep taking it. Tredaptive is not approved in the U.S. but is being watched because of its implications for other heart medicines.

From the letter:

There was a statistically significant increase in the incidence of some types of non-fatal serious adverse events in the group that received TREDAPTIVE and statin compared to the group that received statin without TREDAPTIVE. Preliminary analyses suggest that the events fall within the following broad categories: blood and lymphatic, gastrointestinal, infections, metabolism, musculoskeletal, respiratory and skin. Additional analyses are ongoing to understand the adverse events within these categories.

Tredaptive contains both the B vitamin niacin, used to raise the "good cholesterol," HDL, and to lower triglycerides, and a second drug, laropiprant, which was intended to block the hot flushing in the face and hands that is niacin's main side effect. Because laropiprant was not compared to placebo, it's not possible to tell which side effects were due to the the flush-blocker and which ones were due to niacin, which is widely prescribed to heart patients, mostly in the form of Niaspan, sold by Abbott Laboratories soon-to-be spun off AbbVie unit. Sanjay Kaul, of Cedars Sinai Medical Center, speculated that the gastrointestinal and metabolic side effects might be related to niacin, the others to laropiprant.

For investors, one big concern will be what the results mean for new HDL-boosters, known as CETP inhibitors, being developed by Merck and Eli Lilly. In a big trial of the first CETP inhibitor, Pfizer's torcetrapib, 9 patients who received the drug died from infections compared to 0 in the placebo group. Torcetrapib was never approved.

However, in a 1,600-patient study of Merck's CETP drug, infection was not mentioned as a potential side effect. A Merck spokeswoman says the company continues to believe that medicine "has the potential to be a significant innovation in lipid management." More data will be forthcoming, and results are expected to be presented at a medical meeting and published in a scientific journal. The letter says: "The independent research team at Oxford University is conducting additional analyses, including regional analyses, to further understand the results."